218 PHOTOGRAPHIC FACTS AND FORMULAS 
Potassium ferricyanide 12g O2 ar. 
Water | 1000 ccm 16 oz. 
With all the above baths much more transparent images may 
be obtained by immersion for about 5 minutes in a 5 per cent 
hypo solution. A violet-red tone is obtained (Somerville) by 
treating a copper-toned image with: 
Ammonia-iron alum, 
10% sol. 100 ccm 14 oz. 
Hydrochloric acid 10 ccm 72 min. 
Potassium bromide, 10% sol. 80 ccm 576 min. 
Water 1000 ccm 16 oz. 
Bleach the print in: 
Cupric sulphate 100 g 768 gr. 
Potassium bromide 100 g 768 gr. 
Water 1000 ccm 16 oz. 
Then immerse in a 2 per cent solution of nitric acid for 5 
minutes, wash well, and immerse in a 5 per cent solution of 
sodium sulphite, which gives a brown tone. 
Bleach the print in: 
Potassium ferricyanide 13:5\2 104 gr. 
Potassium bromide 3.5¢ 27 gr. 
Water 1000 ccm 16 oz. 
Wash for 10 minutes; then immerse for 1 minute in: 
Acid potassium oxalate 2/ gs 208 gr. 
Water . 1000 ccm 16 oz. 
Then bathe for a few seconds in a 6 per cent solution of 
ammonia, and immerse in: 
-Cupric sulphate 10 ¢ 77 gr. 
Hydrochloric acid 1.5 ccm 12 min. 
Water 1000 ccm 16 oz. 
Until the desired colour is obtained ; then wash and fix. 
Immerse the prints in (Namias) : 
Rochelle salts 100 g 768 gr. 
